brown discharge or spotting after periodis something wrong?

i am 15 years old and for the past few months i have been getting brown discharge after my period a lot of times lasting for more than 3 days and occasionally a week after my period as well. it's kind of a gooey texture it has no oder sometimes it looks like a blood clot that i normally get during my period and most of the time i see it after i go to the bathroom but sometimes it does show up on my underwear. i told my stepmother about this but she said spotting is normal but everywhere i've looked it says if it happens every month it should be checked out
should i be worried or is it really just normal?